U.S. patent application number 11/945998 was filed with the patent office on 2008-05-29 for methods of posterior fixation and stabilization of a spinal segment.
Invention is credited to BRET A. FERREE.
Application Number | 20080125780 11/945998 |
Document ID | / |
Family ID | 39464627 |
Filed Date | 2008-05-29 |
United States Patent
Application |
20080125780 |
Kind Code |
A1 |
FERREE; BRET A. |
May 29, 2008 |
METHODS OF POSTERIOR FIXATION AND STABILIZATION OF A SPINAL
SEGMENT
Abstract
Methods for spinal stabilization operative to prevent lateral
bending, extension, and rotation across two or more adjacent
vertebrae are described with particular emphasis on preventing
excessive forces on the facet joins. Broadly, the method includes
placing one or more anchors, each having one or more sutures at
each vertebral level on a posterior portion of the vertebrae,
applying tension to the sutures and joining the sutures over the
disc space between two or more vertebra. The sutures can be wrapped
around the spinous process of the adjacent vertebrae.
Alternatively, the sutures can be welded in a cross-braced pattern
extending between the spinous process of the adjacent
vertebrae.
Inventors: |
FERREE; BRET A.;
(CINCINNATI, OH) |
Correspondence
Address: |
O''Melveny & Myers LLP;IP&T Calendar Department LA-1118
400 South Hope Street
Los Angeles
CA
90071-2899
US
|
Family ID: |
39464627 |
Appl. No.: |
11/945998 |
Filed: |
November 27, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60861499 |
Nov 28, 2006 |
|
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Current U.S.
Class: |
606/86R |
Current CPC
Class: |
A61B 2017/0414 20130101;
A61B 17/0483 20130101; A61B 17/7022 20130101; A61B 17/8085
20130101; A61B 17/8861 20130101; A61B 17/0401 20130101; A61B
17/7053 20130101; A61B 17/0469 20130101 |
Class at
Publication: |
606/61 |
International
Class: |
A61B 17/70 20060101
A61B017/70 |
Claims
1. A method for spinal fixation, comprising the steps of: providing
first and second anchors, wherein each anchor carries a first
elongate cable having first and second ends that extend from each
anchor; attaching the first and second anchors across facets in
first and second, adjacent vertebrae; passing said elongate cables
around a spinous process of said first vertebrae and a spinous
process of said second vertebra; and securing the first and second
ends of the elongate cables.
2. The method of claim 1, further comprising securing the first and
second ends of the elongate cables by welding.
3. The method of claim 1, further comprising applying tension to
said elongate cables.
4. The method of claim 1, further comprising implanting an
intrasdiscal device between said first and second vertebrae.
5. A method for spinal fixation, comprising the steps of: providing
first, second, third, and fourth anchors, wherein each anchor
carries a first elongate cable having first and second ends that
extend from each anchor; attaching the first anchor to a posterior
segment of a first vertebra, attaching the second anchor to a
posterior segment of the first vertebra, attaching the third anchor
to a posterior segment of a second vertebra, and attaching the
fourth anchor to a posterior segment of the second vertebra; and
attaching each of the first and second ends of the first elongate
cable of the first anchor to create an attachment with one of the
first and second ends of the first elongate cable of the third and
fourth anchors, attaching each of the first and second ends of the
first elongate cable of the second anchor to create an attachment
with one of the first and second ends of the first elongate cable
of the third and fourth anchors, wherein the elongate cables are
attached in the pattern of a figure-eight having left and right
generally vertically extending segments and diagonal connections
between a spinous process of the first vertebrae and a spinous
process of the second vertebrae.
6. The method of claim 5, wherein each step of attaching is
accomplished by welding.
7. The method of claim 5, wherein the first and second anchors are
attached to pedicles of the first vertebrae and the third and forth
anchors are attached to pedicles of the second vertebra.
8. The method of claim 5, wherein the first and second anchors are
attached to facets of the first vertebra and the third and forth
anchors are attached to facets of the second vertebra.
9. The method of claim 5, further comprising implanting an
interspinous device adapted for placement between the spinous
process of the first vertebra and the spinous process of the second
vertebra.
10. The method of claim 9, wherein the interspinous device is held
in place by one or more elongate cables attached to the posterior
segments of the first and second vertebra.
11. The method of claim 10, wherein the one or more of the elongate
cables pass through the interspinous device.
12. The method of claim 9, wherein the interspinous device
comprises a rigid device composed of a material selected from a
group consisting of: metal, plastic, an in situ curing material,
bone or a bioabsorbable material.
13. The method of claim 9, wherein the interspinous device
comprises a sleeve disposed on one or more elongate cables that
pass between the spinous process of the first and second
vertebrae.
14. A method for stabilizing a spinal segment, comprising the steps
of: providing first, second, third, and fourth anchors, wherein
each anchor carries a first elongate cable having first and second
ends that extend from each anchor; making one or more minimally
invasive surgical openings that provide access to the patient's
spine; attaching the first anchor to a first vertebra, attaching
the second anchor to the first vertebra, attaching the third anchor
to a second vertebra, and attaching the fourth anchor to the second
vertebra, wherein all attachments are performed through the one or
more minimally invasive surgical openings; inserting a first
introducer sheath through one of the one or more minimally invasive
surgical openings to access a region between the first and third
anchors; inserting a second introducer sheath through one of the
one or more minimally invasive surgical openings to access a region
between the second and fourth anchors; and attaching each of the
first and second ends of the first elongate cable of the first
anchor to create an attachment with one of the first and second
ends of the first elongate cable of the third and fourth anchors,
attaching each of the first and second ends of the first elongate
cable of the second anchor to create an attachment with one of the
first and second ends of the first elongate cable of the third and
fourth anchors.
15. The method of claim 14, wherein each step of attaching is
accomplished by welding.
16. The method of claim 14, wherein the elongate cables are
attached in the pattern of a figure-eight having left and right
generally vertically extending segments and diagonal connections
between upper and lower end regions of each vertically extending
segment.
17. The method of claim 14, further comprising the step of drawing
the first and second ends of the first elongate cable or the first
anchor through the first introducer sheath and drawing the first
and second ends of the first elongate cable of the third anchor
through the first introducer sheath.
18. The method of claim 14, further comprising the step of drawing
the first and second ends of the first elongate cable of the second
anchor through the second introducer sheath and drawing the first
and second ends of the first elongate cable of the fourth anchor
through the second introducer sheath.
19. The method of claim 14, wherein the welding is performed
through at least one of the first and second introducer
sheaths.
20. The method of claim 14, wherein the welding is performed using
a welding tool that places the elongate cables under tension.
21. The method of claim 14, wherein one of the first and second
ends of the first elongate cable of the first anchor and one of the
first and second ends of the first elongate cable of the third
anchor are engaged by an elongate instrument inserted through the
first introducer sheath and passed through the second introducer
sheath.
22. The method of claim 14, wherein one of the first and second
ends of the first elongate cable of the second anchor and one of
the first and second ends of the first elongate cable of the fourth
anchor are engaged by an elongate instrument inserted through the
second introducer sheath and passed through the first introducer
sheath.
23. The method of claim 14, wherein the first and second ends of
the first elongate cable of the first anchor are attached under
tension with one of the first and second ends of the first elongate
cable of the third and fourth anchors.
24. The method of claim 14, wherein the first and second ends of
the first elongate cable of the second anchor are attached under
tension with one of the first and second ends of the first elongate
cable of the third and fourth anchors.
Description
RELATED APPLICATIONS
[0001] This application claims the benefit of provisional
application 60/861,499, filed Nov. 28, 2006, entitled "Annulus and
Spinal Ligament Reconstruction." This application is related to
co-pending application 60/808,795, filed May 26, 2006, entitled
"Fastening Assemblies for Disc Herniation Repair and Methods of
Use." The application is also related to U.S. Pat. Nos. 6,248,106
and 6,423,065. All of the above-referenced patent and applications
are hereby expressly incorporated by reference in their
entirety.
FIELD OF THE INVENTION
[0002] The subject invention resides in methods and apparatus for
stabilizing a spinal segment using one or more fixation members
attached to posterior portions of adjacent vertebrae. The invention
is particularly well suited to the prevention of excessive spinal
motion.
BACKGROUND
[0003] The human intervertebral disc is an oval to kidney
bean-shaped structure of variable size depending on the location in
the spine. The outer portion of the disc is known as the annulus
fibrosis (AF). The annulus fibrosis is formed of approximately 10
to 60 fibrous bands or layers. The fibers in the bands alternate
their direction of orientation by about 30 degrees between each
band. The orientation serves to control vertebral motion (one half
of the bands tighten to check motion when the vertebra above or
below the disc are turned in either direction).
[0004] The annulus fibrosis contains the nucleus pulposus (NP). The
nucleus pulposus serves to transmit and dampen axial loads. A high
water content (approximately 70-80%) assists the nucleus in this
function. The water content has a diurnal variation. The nucleus
imbibes water while a person lies recumbent. Nuclear material
removed from the body and placed into water will imbibe water
swelling to several times its normal size. Activity squeezes fluid
from the disc. The nucleus comprises roughly 50% of the entire
disc. The nucleus contains cells (chondrocytes and fibrocytes) and
proteoglycans (chondroitin sulfate and keratin sulfate). The cell
density in the nucleus is on the order of 4,000 cells per
microliter.
[0005] The intervertebral disc changes or "degenerates" with age.
As a person ages, the water content of the disc falls from
approximately 85% at birth to approximately 70% in the elderly. The
ratio of chondroitin sulfate to keratin sulfate decreases with age,
while the ratio of chondroitin 6 sulfate to chondroitin 4 sulfate
increases with age. The distinction between the annulus and the
nucleus decreases with age. Generally disc degeneration is
painless.
[0006] Premature or accelerated disc degeneration is known as
degenerative disc disease. A large portion of patients suffering
from chronic low back pain are thought to have this condition. As
the disc degenerates, the nucleus and annulus functions are
compromised. The nucleus becomes thinner and less able to handle
compression loads. The annulus fibers become redundant as the
nucleus shrinks. The redundant annular fibers are less effective in
controlling vertebral motion. This disc pathology can result in: 1)
bulging of the annulus into the spinal cord or nerves; 2) narrowing
of the space between the vertebra where the nerves exit; 3) tears
of the annulus as abnormal loads are transmitted to the annulus and
the annulus is subjected to excessive motion between vertebra; and
4) disc herniation or extrusion of the nucleus through complete
annular tears.
[0007] Current surgical treatments for disc degeneration are
destructive. One group of procedures, which includes lumbar
discectomy, removes the nucleus or a portion of the nucleus. A
second group of procedures destroy nuclear material. This group
includes Chymopapin (an enzyme) injection, laser discectomy, and
thermal therapy (heat treatment to denature proteins). The first
two groups of procedures compromise the treated disc. A third
group, which includes spinal fusion procedures, either remove the
disc or the disc's function by connecting two or more vertebra
together with bone. Fusion procedures transmit additional stress to
the adjacent discs, which results in premature disc degeneration of
the adjacent discs. These destructive procedures lead to
acceleration of disc degeneration.
[0008] Prosthetic disc replacement offers many advantages. The
prosthetic disc attempts to eliminate a patient's pain while
preserving the disc's function. Current prosthetic disc implants
either replace the nucleus or replace both the nucleus and the
annulus. Both types of current procedures remove the degenerated
disc component to allow room for the prosthetic component. Although
the use of resilient materials has been proposed, the need remains
for further improvements in the way in which prosthetic components
are incorporated into the disc space to ensure strength and
longevity. Such improvements are necessary, since the prosthesis
may be subjected to 100,000,000 compression cycles over the life of
the implant.
[0009] Current nucleus replacements (NRs) may cause lower back pain
if too much pressure is applied to the annulus fibrosis. As
discussed in co-pending U.S. patent application Ser. No. 10/407,554
and U.S. Pat. No. 6,878,167, the content of each being expressly
incorporated herein by reference in their entirety, the posterior
portion of the annulus fibrosis has abundant pain fibers.
[0010] Herniated nucleus pulposus (HNP) occurs from tears in the
annulus fibrosis. The herniated nucleus pulposus often allies
pressure on the nerves or spinal cord. Compressed nerves cause back
and leg or arm pain. Although a patient's symptoms result primarily
from pressure by the nucleus pulposus, the primary pathology Lies
in the annulus fibrosis.
[0011] Surgery for herniated nucleus pulposus, known as microlumbar
diseectomy (MLD), only addresses the nucleus pulposus. The opening
in the annulus fibrosis is enlarged during surgery, further
weakening the annulus fibrosis. Surgeons also remove generous
amounts of the nucleus pulposus to reduce the risk of extruding
additional pieces of nucleus pulposus through the defect in the
annulus fibrosis. Although microlumbar discectomy decreases or
eliminates a patient's leg or arm pain, the procedure damages
weakened discs.
SUMMARY
[0012] A portion of the anulus fibrosis and a portion of the
ligaments of the spine are excised to allow insertion of materials
and devices into the disc space. For example, a portion of the
anterior half of the anulus fibrosis and a portion of the anterior
longitudinal ligament (ALL) are excised to enable insertion of bone
growth promoting materials and fusion devices in interbody fusion
procedures. Removal of portions of the anulus fibrosis and anterior
longitudinal ligament increase the flexibility of the spine and
allow excessive motion of the spine. For example, removal of the
tissues mentioned permits excessive spinal extension, lateral
bending, and axial rotation. Destabilizing the spine decreases the
chance of a successful fusion. The invention may be used to
increase the stiffness of the operated segment of the spine.
Increasing the stiffness of the spine facilitates spinal
fusion.
[0013] A portion of the anulus fibrosis and a portion of the
anterior longitudinal ligament are also excised to enable insertion
of motion preserving devices into the disc. For example, Total Disc
Replacements (TDRs) and Nucleus Replacements (NRs) are often
inserted through the anterior portion of discs. Excessive spinal
extension, lateral bending, and axial rotation following excision
of the spinal tissues and insertion of motion preserving devices
into the disc space places excessive force on the facets of the
spine. Biomechanical studies show the forces across the facets at
the operated level of the spine can be doubled by motion preserving
devices and the techniques used to insert such devices. Excessive
force on the facets may lead to degeneration of the facets.
Degeneration of the facets may cause low back pain.
[0014] The present invention provides methods for spinal
stabilization on the posterior portions of adjacent vertebrae
operative to prevent lateral bending, extension, and rotation
across a spinal segment with particular emphasis on preventing
excessive forces on the facet joints of the spine.
[0015] In some embodiments, first and second anchors can be
attached across adjacent facets in two adjacent vertebrae. Each
anchor has at least one suture passing therethough. The sutures can
be passed around the spinous processes of the adjacent vertebrae
and joined together to join the two adjacent vertebrae. The sutures
can be joined by welding or any other suitable technique known in
the art for joining the two ends of a suture. Tension can be
applied to the sutures prior to joining to apply compression to the
vertebrae and to prevent excessive spinal extension, lateral
bending, and axial rotation of the spinal segment thereby reducing
the forces placed across the facets. In some embodiments, one or
more suture anchors and sutures can also be arranged across
anterior portions of the adjacent vertebrae to further apply
compression to the vertebrae and to prevent excessive spinal
extension, lateral bending, and axial rotation of the spinal
segment. The combination of anterior and posterior sutures can also
be used to hold an intradiscal device in place between the adjacent
vertebrae.
[0016] In some embodiments, first and second anchors can be placed
on posterior potions of two adjacent vertebrae. The anchors can be
placed, for example, in the facets or pedicles of the vertebrae.
The anchors placed in the cranial and caudal vertebrae each have at
least one elongate member, such as a suture, extending
therethrough. Tension is applied to the elongate members and the
elongate are attached in the pattern of a figure-eight having left
and right generally vertically extending segments and diagonal
connections between a spinous process of the first vertebrae and a
spinous process of the second vertebrae. In some embodiments, the
elongate members on the posterior portions of the vertebrae can
also be used to hold an intraspinous device in the interspinous
space between two adjacent vertebrae.
[0017] In some embodiments, the sutures can be placed in the
posterior portions of the vertebrae through one or more minimally
invasive openings. One or more minimally invasive surgical openings
are made to provide access to the patient's spine. First and second
anchors can be placed on posterior potions of two adjacent
vertebrae, such as the facets or pedicles, via the minimally
invasive openings. Each anchors placed has at least one elongate
member, such as a suture, extending therethrough. An introducer
sheath or retractor is inserted through one of the one or more
minimally invasive surgical openings to access a region between the
first anchors on each vertebra and a second introducer sheath
through one of the one or more minimally invasive surgical openings
to access a region between the second anchors on each vertebra. The
elongate members are arranged via the introducer sheaths and then
tension is applied to the elongate members and the elongate members
are attached in the pattern of a figure-eight having left and right
generally vertically extending segments and diagonal
connections.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1A illustrates a posterior view of segment of a spine
with suture anchors placed across the facet joints between two
adjacent vertebrae.
[0019] FIG. 1B illustrates a posterior view of the embodiment in
FIG. 1A with sutures placed over the spinous processes of the
vertebrae and joined together.
[0020] FIG. 2A illustrates a lateral view of an alternative
embodiment for stabilizing a spinal segment illustrating both
posterior and anterior placed suture stabilization.
[0021] FIG. 2B illustrates an anterior view of the embodiment in
FIG. 2A showing sutures on the anterior portion of the vertebrae
joined together in a cross-braced pattern.
[0022] FIG. 3A illustrates a posterior view of a segment of a spine
with suture anchors placed in the facet joints of two adjacent
vertebrae and sutures joined together in a cross-braced pattern
between the spinous processes.
[0023] FIG. 3B illustrates a lateral view of a sagittal cross
section of the embodiment in FIG. 3A illustrating both posterior
and anterior placed suture stabilization.
[0024] FIG. 3C illustrates a lateral view of a sagittal cross
section of the embodiment in FIG. 3B illustrating an interspinous
device placed between the spinous processes.
[0025] FIG. 3D is posterior view of an alternative embodiment in
FIG. 3B illustrating the posterior sutures passing through the
interspinous device placed between the spinous processes.
[0026] FIG. 3E is posterior view of an alternative embodiment in
FIG. 3D illustrating the posterior sutures having sleeves passing
between the spinous processes.
[0027] FIG. 4A is a top view of a cross-section of a vertebra
illustrating an embodiment of a method for placing sutures in the
posterior portions of a spinal segment via minimally invasive
openings.
[0028] FIG. 4B is a posterior view of the embodiment in FIG. 4A
showing four small incisions in a patient's back for placing suture
anchors and sutures in two adjacent vertebrae.
[0029] FIG. 4C is a posterior view of the embodiment in FIG. 4B
showing two additional incisions between the four original
incisions.
[0030] FIG. 4D is a posterior view of the embodiment in FIG. 4C
showing retractors placed in the two medial incisions.
[0031] FIG. 4E is a posterior view of the embodiment in FIG. 4D
showing the hook end of the instrument drawn in FIG. 7 was passed
through the tube retractor, under the skin and through the muscles
of the back.
[0032] FIG. 4F is a posterior view of the embodiment in FIG. 4E
showing ends of the sutures pulled through the retractors with the
hook-shaped instrument.
[0033] FIG. 4G is a posterior view of the embodiment in FIG. 4F
showing a welding tool has been placed over the first ends of a
suture from an anchor in the cranial vertebra and a suture from an
anchor in the caudal vertebra.
[0034] FIG. 4H is a posterior view of the embodiment in FIG. 4G
showing the welded ends of the sutures through the two retractors
placed in the two medial incisions.
[0035] FIG. 4I is a posterior view of the embodiment in FIG. 4G
showing the closed incisions.
[0036] FIG. 5 is an oblique view of a tube-shaped retractor
[0037] FIG. 6 is an oblique view of a tool for use in the
embodiment of the invention drawn in FIGS. 4A-I.
[0038] FIG. 7 is a lateral view of an alternative hook shaped tool
for use in the embodiment of the invention drawn in FIGS. 4A-I.
[0039] FIG. 8 is a lateral view of an alternative hook shaped tool
for use in the embodiment of the invention drawn in FIGS. 4A-I.
[0040] FIG. 9A is posterior view of a portion of patient's back
showing second ends of sutures in the cranial and caudal vertebrae
pulled through a first retractor with the hook shaped
instrument.
[0041] FIG. 9B is a posterior view of the embodiment in FIG. 9A
showing the second ends of the sutures passed from a first
retractor to the second retractor with the hook-shaped
instrument.
[0042] FIG. 9C is a posterior view of the embodiment in FIG. 9B
showing the second ends of the sutures pulled through the second
retractor.
[0043] FIG. 9D is a posterior view of the embodiment in FIG. 9C
showing the second ends of the sutures joined together in a
criss-cross pattern beneath the skin.
[0044] FIG. 10A is an exploded lateral view of an embodiment of a
suture anchor.
[0045] FIG. 10B is an exploded lateral view of an alternative
embodiment of a suture anchor.
DETAILED DESCRIPTION
[0046] FIGS. 1A-1B illustrate a method using two sutures to join
adjacent vertebrae across the facet joints to prevent and/or
minimize flexion, lateral bending and rotation across a spinal
segment with particular emphasis on preventing excessive forces on
the facet joints of the spine. As shown in FIG. 1A, suture anchors
10a, 10b are placed across the facet joints 101a,b and 103a,b
between the adjacent vertebrae 100 and 102. Each suture anchor
10a,b has at least one eyelet for threading sutures 6a,b. Sutures
6a,b, are threaded through the single eyelets in anchors 10 a,b
respectively such that first and second ends of each suture 6a,b
extend from anchors 10 a,b.
[0047] In some embodiments, the sutures can be monofilament or
multifilament configurations of nylon, polypropylene, polyester,
polyethylene, or other material. For example in one embodiment, the
sutures can be made from a #5 polyester multifilament material. In
another embodiment, the sutures can be made of a #5 resorbable
multifilament suture such as VICRYL.TM. (Ethicon, N.J.). In other
embodiments, suture materials can be selected for specific
characteristics. For example, rigid, semi-rigid or elastic
materials may be selected. In embodiments of the invention used in
spinal fusion procedures relatively inelastic sutures are
preferably used. In other embodiments, the sutures can be made of
materials than can be welded together.
[0048] As shown in FIG. 1B, the sutures 6a,b are placed around the
spinous processes 104, 105 of the adjacent vertebrae and joined
together. Tension is applied to the sutures 6a,b prior to joining
together to apply compression to the vertebrae 100, 102 and thereby
limit spinal flexion, lateral bending, and axial rotation. The ends
of sutures 6a,b can be joined together by any suitable method known
in the art such as a knot, crimping, melting, welding or otherwise
fusing the two ends of the suture. In the illustrated embodiment,
the ends of sutures 6a,b are welded together. The weld is
preferably caused by heat-generating or heat-conducting
instruments. The heat may be generated ultrasonically or by other
means. Instruments with special tips may be used to weld the
sutures within deep areas of the body. For example, instruments
that are about 15 to abut 45 cm in length may be needed to weld
sutures in the abdomen or through the muscles in the back. The
welding instruments are preferably about 4 to about 8 mm in
diameter. In some embodiments, tension can be applied to the
sutures 6a,b before the sutures 6a,b are welded together.
[0049] In some embodiments, as shown in FIG. 2A, an intradiscal
device 108, such as a bone graft or fusion cage can be placed into
the disc space 106 between vertebrae 100, 102. The intradiscal
device 108 carries the axial load between the vertebrae 100, 102.
The intradiscal device 108 also helps limit spinal flexion. The
intradiscal device 108 is preferably wedge-shaped and at least as
tall as the disc space 106. Such size and shape of the intradiscal
device 108 helps to maintain the normal lordosis of the spine
despite application of compression to the anterior portion of the
spine. Alternatively, the intradiscal device 108 can be
wedge-shaped and 1, 2, 3, 4, 5, 6, 7, or more millimeters taller
than the disc space. As shown in FIGS. 1A-B and 2A anchor 10a is
placed across facets 101a and 103a. Sutures 6a and 6b are threaded
through anchors 10a,b, placed around spinous processes 104 and 105.
Tension is applied to sutures 6a,b and they are then welded
together to maintain the tension and apply compression to vertebrae
100 and 102 and to intradiscal device 108. The tension on the
posterior portion of the spine limits spinal flexion, lateral
bending, and axial rotation.
[0050] In addition, in some embodiments, anchors 10c,d,e,f can be
placed in the anterior portion of vertebrae 10, 102 and sutures
6c,d,e,f can be threaded through anchors 10c-f and welded together
to connect the anterior portions of vertebrae 100, 102 as shown in
FIGS. 2A-B and described in more detail in co-pending application
entitled "SUTURE WELDING", filed on Nov. 27, 2007, and provisional
application 60/861,499, filed Nov. 28, 2006, entitled "Annulus and
Spinal Ligament Reconstruction, all of the which are hereby
expressly incorporated by reference in their entirety. Tension is
applied to sutures 6c,d,e,f prior to welding to maintain the
tension and apply compression to vertebrae 100 and 102 and to
intradiscal device 108. The tension on the anterior portion of the
spine limits spinal extension, lateral bending, and axial
rotation.
[0051] FIGS. 3A-B illustrates an alternative embodiment of a method
for applying sutures to maintain tension on the posterior portion
of spine and apply compression to the vertebrae to limit spinal
flexion, lateral bending, and axial rotation thereby reducing the
forces placed across the facet joints. As shown in FIG. 3A, anchors
30a,b,c,d are placed in pedicles 111a,b and 112a,b of vertebrae
100, 102. In alternative embodiments, the anchors 30a,b,c,d can be
placed in other suitable posterior segments of the vertebrae,
100,102 such as the facets. Sutures 36a,b,c,d are threaded through
anchors 30a,b,c,d respectively such that first and second ends of
each suture 6a,b,c,d extend from anchors 30a,b,c,d.
[0052] The medial ends of sutures 36a and 36c and of 36b and 36d
are joined in a diagonal, crisscrossed pattern between spinous
processes 104, 105 and over the disc space between vertebrae 100
and 102. The lateral ends of the sutures 36a and 36b and of 36c and
36d are likewise joined together to create vertical fixation suture
arms. The sutures can be connected using any suitable methods known
in the art such as a knot, crimping, melting, welding or otherwise
fusing the two ends of the suture. In the illustrated embodiment,
tension is applied to sutures and they are then welded together to
maintain the tension between and apply compression to the posterior
portion of vertebrae 100, 102. The weld is preferably caused by
heat-generating or heat-conducting instruments. The heat may be
generated ultrasonically or by other means.
[0053] This configuration joins the adjacent vertebrae 100 and 102
forms an "X" over the disc space between vertebrae 100 and 102. The
vertical and a diagonal configuration of the sutures 36 a,b,c,d
over the disc space advantageously provides an arrangement that
resists and/or limits flexion, lateral bending and axial
rotation.
[0054] In some embodiments, as shown in FIG. 3B, an intradiscal
device 108 can be inserted into the disc space 106 between
vertebrae 100,102 and sutures can be applied to the anterior
portion of vertebrae 100, 102 as well to apply tension on the
anterior portion of the vertebrae and thereby limit spinal
extension, lateral bending, and axial rotation. As shown in FIG.
3B, and discussed above in reference to FIG. 2A, anchors 10c,d,e,f,
can be placed in the anterior portion of vertebrae 100, 102 and
sutures 6c,d,e,f can be threaded through anchors 10c-f and welded
together to connect the anterior portions of vertebrae 100, 102.
Tension is applied to sutures 6c,d,e,f prior to welding to maintain
the tension between and apply compression to vertebrae 100 and 102
and to intradiscal device 108. Applying tension to both the
anterior and posterior portions of vertebrae 100, 102 applies
compression to the intradiscal device 108 and vertebrae 100, 102
and limits spinal flexion and extension, lateral bending, and axial
rotation. In some embodiments, the sutures 6c-f and 36a-d can be
different sizes and/or made of different materials such that the
sutures have different tensile strength, elasticity or other
properties in order to vary the resistance to the resistance to
spinal extension, flexion, lateral bending and axial rotation
extension as necessary. For example, in one embodiment, the
anteriorly placed sutures 6c-f could be a #5 polyester
multifilament material. The posteriorly placed sutures 36a-d could
be made of VICRYL.TM.. Alternatively, in some embodiments, one set
of sutures could be more elastic than the second set of sutures.
For example, one set of sutures 6c-f could reversibly stretch about
1 to about 10 mm. The other set of sutures 36a-d could reversibly
stretch about 5 to about 8 mm.
[0055] In some embodiments, one or more sutures on the posterior
segment of the spine can also be used to hold an intraspinous
device in the interspinous space between two adjacent vertebrae.
FIG. 3C, is a lateral view of a sagittal cross section of the spine
and an alternative embodiment of the invention having an
intraspinous device 110 in the interspinous space 109 between
spinous processes 104 and 105. The relatively incompressible device
carries axial load from one spinous process to the other spinous
process. The device could be made of metal (such as titanium,
plastic (such as PEEK), bone, an in-situ curing material (such as
polymethylmethacrylate (PMMA), bioresorbable materials including
in-situ curing materials such as bioactive cements or any other
suitable material known in the arts. In one embodiment, the PMMA
could be injected into a removable mold. Alternatively, the PMMA
could be injected into a second device, such as a bag or tube that
was previously placed between the spinous processes. Alternatively,
the PMMA could be inserted after curing outside the body. The use
of PMMA to stabilize the spine is well known to those skilled in
the art.
[0056] As shown in FIG. 3D, in some embodiments, the diagonal
flexible fixation members 36ac and 36bd can be threaded through the
intraspinous device 110 between the spinous processes 104 and 105.
For example, sutures 36a and 36b can be threaded through device 110
prior to welding suture ends 36a to 36c and 36b to 36d to create
the diagonal fixation members 36ac and 36bd. The diagonal fixation
members 36ac and 36bd can hold intraspinous device 110 in place
between the spinous processes 104 and 105. In some embodiments,
tension can be applied to suture ends 36,b,c,d prior to welding
such that diagonal fixation members 36ac and 36bd apply tension to
the posterior portion of the vertebrae 100 and 102 as well as hold
intraspinous device 110 in place.
[0057] In an alternative embodiment, shown in FIG. 3E, the diagonal
flexible fixation members 36ac and 36bd are threaded through
sleeves 38a and 38b. The sleeves 38a,b are made of relatively
incompressible materials. For example, the sleeves can be made of
metal (such as titanium, plastic (such as PEEK), bone, an in-situ
curing material (such as polymethylmethacrylate (PMMA),
bioresorbable materials including in-situ curing materials such as
bioactive cements or any other suitable material known in the art.
The relatively incompressible sleeves 38a,b carry the axial load
from one spinous process to the other spinous process. As discussed
above, in some embodiments, tension can be applied to the sutures
36a,b,c,d prior to welding to create tension across diagonal
fixation members 36ac and 36bd and limit flexion, lateral bending
and axial rotation of the spine.
Percutaneous Posterior Suture Based Stabilization
[0058] In some embodiments, the sutures can be placed in the
posterior portions of the vertebrae through one or more minimally
invasive openings. As shown in FIGS. 4A-B, one or more minimally
invasive surgical openings 42a,b,c,d are made through a patients
skin 41 to provide access to the patient's spine. First and second
anchors 40a,b are be placed on posterior potions of the vertebrae
400 via the minimally invasive openings 42a,b. Likewise, first and
second anchors 40c,d (not shown) are placed on posterior potions of
an adjacent vertebrae (not shown) via the minimally invasive
openings 42c,d. The minimally invasive openings 42a,b,c,d are
preferably less than 6 mm. Alternatively, the incisions could be 4,
5, 6, 7, 8, 9, or more millimeters long. The anchors 40a,b,c,d can
be placed into the pedicles of the vertebrae 400, 402, for example
as shown in FIGS. 3A and 3B in respect to vertebrae 100, 102.
Alternatively, the anchors 40a,b,c,d can be placed in any suitable
segment of the posterior portion of the vertebrae such as the
facets or the spinous processes.
[0059] Each anchor 40a,b,c,d placed has at least one elongate
member, such as a sutures 46a,b,c,d, extending therethrough The
sutures 46a,b,c,d are seen coursing from the anchors and through
the stab wounds. The sutures 46a,b from the cranial set of anchors
40a,b are preferably a different color than the sutures 46c,d in
the caudal set of anchors 46c,d.
[0060] As shown in FIG. 4C, two additional incisions 48a and 48b
are made between the openings 42a and 42c and 42b and 42d. The
incisions 48a and 48b are used to provide access for manipulating
the ends of sutures 46a,b,c,d. The incisions are preferably less
than 10 mm each. Alternatively, the incisions could be 6, 7, 8, 9,
10, 11, 12, 14, or more millimeters long.
[0061] As shown in FIG. 4D, a first retractor 50a is placed through
incisions 44a and a second retractor 50b is placed through incision
48b to hold the incisions 48a,b open and provide a passageway for
accessing the sutures 46a,b,c,d at a point close to the suture
anchors 40a,b,c,d. As shown in FIG. 5, the retractor 50 has a
tubular shape to holds back surrounding tissue and organs, so that
the vertebra can be accessed. Alternatively, the retractor could
have features that allow expansion of the retractor in-situ to
access to the spine. Furthermore, the retractor could have two or
more blades that expand rather than a continuous tube.
[0062] As shown in FIG. 4E, a hook shaped tool 60 passed through
the tube retractor, under the skin and through the muscles to
access the suture 46b at a point close to the anchor 40b (not
shown). FIG. 6 is an oblique view of the tool 60 used in the
embodiment of the invention drawn in FIG. 4E. The instrument
preferably has a hook 62 n one end and a bayonet handle 61 at the
opposite end of the tool. In an alternative embodiment as shown in
FIG. 7, the tip 72 of the hook shaped tool 70 can have a slot 74 at
the end. Alternatively, the tip 82 of the tool 80 can be cannulated
84, as shown in FIG. 8.
[0063] The hook shaped end 62 of the tool is used to grasp suture
46b and pull both ends of the suture back through incision 42b,
through the muscles and up through retractor 50b. Fluoroscopy may
used to help align the hook over the anchor. In some embodiments,
the suture may also be manipulated into the hook 62 with a
cannulated sleeve over the sutures.
[0064] As shown in FIG. 4F, the process is repeated until the ends
of each suture 46a,b,c,d have been drawn through the muscles and up
through retractors 50a and b. Dotted lines show the path of each
suture 46a,b,c,d across the muscle tissue and under the skin to the
retractors 50a and b. The ends of the sutures 46a and c are
extending from retractors 50a sutures 46b and d extending from
retractor 50b can now be joined together.
[0065] As shown in FIG. 4G a welding tool 90 has been placed over
one end of suture 46b from an anchor in the cranial vertebra one
end of suture 46d from an anchor in the caudal vertebra. The tip of
the instrument is passed through the retractor sleeve 50b. Tension
is applied to the first ends of the sutures 46b and d and the
sutures 46b and d are welded together. Fluoroscopy may be used to
help guide the tip of the welding tool 90 to the level of the
anchors. The process is repeated with the second ends of sutures
46b and d to create a pair of vertical fixation arms 46bd, as shown
in FIG. 4H, joining adjacent vertebrae 400 and 402. Similarly,
welding tool 70 is placed over first ends of suture 46a and c and
passed through the retractor sleeve 50b. Tension is applied to the
first ends of the sutures 46a and c and the sutures 46ba and c are
welded together. The process is repeated with the second ends of
sutures 46a and c to create a second pair of vertical fixation arms
46ac, as shown in FIG. 4H, joining vertebrae 400 and 402. Once the
sutures have been welded together, the excess suture is removed,
the retractor tubes 50a,b are removed and the incisions 42a,b,e,d
and 48a,b are closed as shown in FIG. 4I.
[0066] In an alternative embodiments, as shown in FIGS. 9A-D the
sutures 46a,b,c,d can be arranged in a cross-braced pattern as
described in reference to FIG. 3A. Here, as shown in FIG. 9A, the
first and second ends of sutures 46a,b,cd are drawn through
retractors 50a and b as discussed above with respect to FIGS. 4E-F
and the first ends of the sutures 46a and b from the anchors in the
cranial vertebrae are welded to the first ends of the sutures 46c
and d from the anchors in the in the caudal vertebra to create
single vertical fixation arms 46ac and 46bd similar to the process
described in FIGS. 4G-4H. The welded portions of the sutures can be
seen through the tube retractors 50a,b. However, as shown in FIG.
9A-B, the second ends of the sutures 46a,c from the cranial and
caudal anchors on the right side of the spine are grasped by the
hook shaped tool 70 and the tool 70 is passed through retractor 50a
under the patients skin and up through retractor 50b to thread the
second ends of sutures 46a,c from the right side of the spine
through retractor 50b on the left side of the spine. The second
ends of the sutures 46a and 46d and the second ends of sutures 46b
and d are then welded together via a welding tool inserted through
the retractor 50b to create diagonal fixation arms 46ad and
46bc.
[0067] FIG. 10A is an exploded lateral view of anchor for use in
methods of minimally invasive spinal stabilization. The anchor has
a first portion 11 for attaching to the vertebra. The first portion
11 is cannulated so that a guide wire can be threaded through the
first portion 11 for guiding the anchor to the vertebra through a
minimally invasive opening. A second component 12 contains at least
one eyelet for threading a suture 6 therethrough. As shown in FIG.
10B, the second component 12 can be fastened to the threaded
portion 11 of the anchor after the anchor is inserted into the
spine and the guide wire is removed. In some embodiments, the
components could be fastened together using shape memory fastening
technology. Alternatively, the components could be threaded
together or a cam-lock could be used to hold the components
together.
[0068] Although the foregoing invention has, for the purposes of
clarity and understanding, been described in some detail by way of
illustration and example, it will be obvious that certain changes
and modifications may be practiced which will still fall within the
scope of the appended claims.
* * * * *